Respuesta :

final concentration of NaOH = 0.14*500/(500+535) = 0.0676 M ( = concentration base)

final concentration of acid = 0.2*535/(500+535) = 0.1034 M - 0.0676 M = 0.0358

 

Therefore pH is:

pH = -log(7.12 x 10^-5) + log(0.0676/0.0358)

pH = 4.42